Regulator for aircraft driving



Dec. 12, 1939. P. E. KOSTER REGULATOR FOR AIRCRAFT DRIVING GEARSOriginal Filed April 18, 1935 INvE/v oR RULIDUARDKO 57-51 n-744m? Pl 5259a Km Reisaued Dec. 12, 192.9

PATENT. OFFICE REGULATOR FOR AIRCRAFT DRIVING GEARS Paul Eduard Kiister,Berlin, Germany, assignor to Siemens Apparate und Maschinen G. in. b.IL, Berlin, Germany, a corporation or Germany Original No. 2,112,965,datedApril 5,1938, Serial No. 17,049, April 18, 1935. Application forreissue June 14, 1939, Serial No. 279,105. In Germany April 19,1934

12 Claims. (or. 244- 16) My invention relates to aircraft power plantsand, more particularly, to means for regulating the power plant of anaeroplane having an internal combustion engine and a variable pitchpropeller driven by the engine.

According to the invention the power plant is value of the speedgovernor and/ or of the charging pressure regulator.

By charging pressure is understood the intake pressure in front of thecylinder valves of the engine, that is to say, the pressure at which thegas mixture is supplied from the carburettor to the cylinders of thedriving engine.- Regulators for regulating this charging pressure arewell known in the art and as the details of these devices are not inthemselves part of my invention the description thereof is limited towhat is necessary in order to make the invention of this applicationunderstood. Also governors are well known which vary the angle of attackof the controllable propeller in accordance with suitable magnitudes,for instance, with the speed, so as to maintain constant said regulatingmagnitude, i. e., for instance, the speed. The invention does not,therefore, lie in the constructive details of the governor or regulatorunder consideration, not even in the use of either the governor or thecharging pressure regulator, but rather in the provision oi a.regulating device for the power plant of an aeroplane by combining thespeed governor and the charging pressure regulator.

The advance attained thereby will be apparent from the followingconsiderations. The power of an aeroplane engine is substantiallydetermined by the speed and the charging pressure. If, consequently, thespeed and the charging pressure are maintained constant, the power ofthe engine will, therefore, also remain constant during the v periodthat the speed and the charging pressure are maintained constant. 7 Itis thereby possible to operate by means of the novel regulating devicein all attitudes of flight with a constant power of the engine. With thenovel regulating device it is possible to prevent the power plant,irrespective of the attitude of flight, from being loaded beyond theabove-mentioned constant power value. If thementioned power value is themaximum power of the engine, the novel regulating device, consequently.permits of utilizing the power plant at maximum load without, however,running the risk of overloading the engine, for instance, owing to achange of the attitudetof flight. This is very important both in civiland military aeronautics. Particularly, in the lastmentioned case anoverload must at all events be prevented. 0n the other hand, there isalso a great interest in utilizing always the permissible maximum load.The engine with the aid of the regulating-device is at all heightsstressed at the desired power uniformly and, under circumstances, inaccordance with the adjustment of the speed governor and chargingpressure regulator when the aeroplane takes oil, climbs, flies at highspeeds and at certain accelerated fly ng attitudes.

The novel regulating device may also be employed to advantage,particularly in connection with multi-engined aeroplanes.

With certain types of known-automatic control devices the driving gearis regulated in accordance with the height of flight measured, forinstance, with a barometer, so as to maintain the adjusted height offlight at a constant value. According to the invention this result isaccomplished by adjusting the regulating value to be maintained constantby the charging pressure regulator in accordance with an instrument forindicating the height of flight.

Further details of the invention will be apparent from the followingdescription taken in connection with the acocmpanying drawing in whichFig. 1 shows an embodiment of the regulating device according-to theinvention;

Fig. 2 shows a multi-engined aeroplane whoseengines are equippedwith thenovel regulating device, the adjustment of the regulating values.

to be maintained constant by these regulating devices being effectedfrom a central point;

. Fig. 3-shows a top view of one of the regulatingdevices of theembodiment shown in Fig. 2; Fig. 4 illustrates a top view of the secondreg-,- ulating device of the embodiment shown in Fig. 2; Fig. 5 shows afront elevational view of the regulating device according to Fig. 3 orFig. 4;

engagement with a bevel gear 8 rotatably mounted on the engine shaft 3.The bevel ar a is connected to rotate in unison with a gear 9 meshiingwith a gear Ill. The gear III is so arranged on the shaft II with theaid of a wedge or feather Ilb extending through a groove of the hub ofthe gear III that it revolves together with the shaft l I, the latterbeing capable of sliding in its longitudinal direction relatively to thegear III. The gear I is prevented from shifting in the longitudinaldirection of the shaft II by a flanged collar lfla and a bearing bracketI2. The shaft II is provided with a thread having a steep pitch as shownat Ila. At this point the gear l3 whose hub is provided with an internalthread corresponding to the thread Ila is mounted on the shaft II. Thegear I3 is held in such a manner by a flanged collar I31! and a bearingbracket I2 as to prevent it also from being shifted in the longitudinaldirection of the shaft II. A longitudinal displacement of the shaft llonly causes, owing to the thread I la, a rotation of the gear I!relatively to the shaft II. The gear I! meshes with a gear I firmlymounted on the engine shaft 3.

The operation of the parts so far described is as follows:

Assuming that the shaft 3 rotates with any speed whatever, the revolvingmovement is transmitted through the gear I4 and the gear l3 to the shaftII and then to the gear ll through the gear Ill. The gears I4 and iihave a ratioof 1:1. Consequently; the gear 9 revolves with the samespeed with which the gear ll rotates and, therefore,

with the same speed as the engine shaft 3. The

- changed. This applies to the case in which the 8 opposite to theaction of the spring I50.

shaft II is not shifted in the longitudinal direction.

If the angle of attack of the propeller l, 5 is to be varied, the shaftll must be shifted in its longitudinal direction by a correspondingamount. This results in a rotation of the shaft ll relatively to thegear I3; This rotation is transmitted to the bevel gear ll through thegears Ill and 9, that is to say, the bevel gear 8 is rotated relativelyto the shaft 3 in the one or the other direction, depending upon thedirection of displacement of the shaft II, with the result that theangle of attack of the propeller blades 4 and i is alteredcorrespondingly. By a displacement of the shaft I I it is, therefore,possible to change the angle of attack of the propeller during itsrotation.

As above described the angle of attack is varied in accordance with aspeed governor. This consists in the embodiment shown of a centrifugalgovernor l5 which is secured to the shaft 3 as indicated at liar andwhich with increasing speed shifts the plate lib in the direction of theshaft In order. that the movements of the plate lib may causecorresponding variations in the angle of attack of the propeller, ahydraulic or pneuma ic servo-motor arrangement is provided consisting ofthe servo-motor l6 and of the regulating slide valve II. The one end ofthe piston rod lBa of the servo-motor l6 and the end of the shaft Ilprovided with a flange Ilc are coupled in the longitudinal directionwithout any appreciable clearance in such a manner as to permit theshaft ll of rotating relatively to thepiston rod lie. The

.one end of the piston rod lie of the slide valve II engages theplate'lsb in a similar manner so that the plate lib is, therefore, notprevented from rotating and that nevertheless displacements of v the.plate lib in the direction of the shaft 3 cause maintained constant bythe governor, the casing of the slide valve I1 is so arranged on guideblocks "and I! as to slide in the direction of the piston rod Ho. Thecasing of the slide valve I1 carries a gear rack I'ld meshing with agear segment l1! pivotally mounted as indicated at lie. The gear segmentIIf may be rocked opposite to the action of the spring Hg with the aidof a control line 2. by means of the adjusting device 34 arrangedpreferably at the pilot seat. Rocking the gear segment l'lf causes, aswill be readily apparent, an adjustment of the casing of the slide valveI'I. Since the slide valve l |.-is slidably arranged, flexible conduitsmust be employed for the conduits 22 and 23 leading to the servo-motorl8.

. 2i denotes the conduit through which the aeroengine 2 is supplied withgas mixture, the conduit being enlarged as indicated at 2|. Within thespace thus enlarged there is a gas-tight diaphragm capsule 26 of thesame type as those employed in barometers etc. The diaphragm capsule isevacuated to such as extent that it is sufilciently sensitive in thefluctuations of the pressure of the gas mixture flowing through thespace 25, i. e., its expansion is increased or decreased in accordancewith the gas pressure.

The one end of the diaphragm capsule 26 is secured to a rod 21 which isguided in the wall of the casing in a manner as tight as possible. Theone end of the piston rod 200, of a slide valve 28 serving to controlthe servo-motor 2! is secured to the other end of the diaphragm. capsule28. The servo-motor 28 cooperates with a throttle 30 placed in a conduit3| through which the air is supplied to the carburettor or to the blowerfeeding the engine.

The regulating value to be maintained constant by the charging pressureregulator may be varied by shifting the rod 21 in its longitudinaldirection. To this end, the rod 21 is connected by a pivot joint withone end of a lever 32 pivotally mounted as indicated at 32a. The otherend of the lever 32 which is under the'influence of a spring may beadjusted through a control line 33 by means .of the adjusting device.34. Thisadjusting dethe device shown in Figure 6, so far as theelements Ell to 59 and 62 to 64 of that figure are concerned, andincludesan electric motor for driving the drum Iill, an altimeter forcontrolling the motor and a flexible shaft" with a crank handle 58 andascale 11 for adjusting the altitude which is to be maintainedautomatically.

The operation of the arrangement, as far as it is shown in Figure 1, isasfollows:

It may be assumed that the device is in operation and both the speed andthe charging pres-- sure correspond to the values to be maintainedconstant. In this case the pistons of the slide valve I1 and of theslide valve 28 respectively are in the zero position illustrated. If thespeed now should increase or decrease for any reason whatever, the platel5b of the centrifugal governor I! will move and operatethe servo-motorIS in the one or the other direction, to shift the shaft ll lengthwiseand thus cause a partial rotation of Said shaft relatively to the wheelII- slide valve l1 returns to the zero position.

whereby the wheel 9 -will be given a partial rotation relatively to thewheel l4, resulting in a. change in the angle of attack of the propelleruntil the desired speed is again attained and the If the speed to bemaintained constant is to be increased or decreased, the adjustingdevice 34 is actuated in a corresponding manner, with the result thatthe casing of the slide valve 11 is shifted in the one or the otherdirection and the servo-motor I is put into operation accordingly.Thereupon the angle of attack of the propeller is varied until thepistons of the slide valve I! reach the zero position with respect tothe corresponding cylinder owing to the change in speed caused by thevariation of the angle of attack.

If the charging pressure varies the expansion of the diaphragm capsule26 is increased or decreased'in the direction of the rod 28a with the iresult that the servo-motor 29 adjusts the throttle 30 until the desiredvalue of charging pressure is again established.

If it is desired to change the value to be maintained constant by thecharging pressure regulator, the adjusting device 34 is actuated byactuating the crank handle 65 until the pointer,

of scale 11 shows the new altitude to be maintained constant.Thisadjustmenthas the result that the slide valve 28 is actuated by thedisplacement of the rod 21 thus putting the servo-motor 29 intooperation. The latter adjusts the throttle 30 until the regulating slidevalve 28 has returned to the zero position through the change inpressure prevailing in the chamber 25. Details of the -'adjusting device34 and of its operation are described hereinafter with reference to Fig.6.

As above described the regulating device according to the invention isparticularly advantageous when used in connection with multi-enginedaeroplanes. Fig. 2 illustrates a multi-engined aeroplane embodying myinvention. The aeroplane 4|) is equipped with four engines 4|, 42, 43,and 44. Since. the regulating device for the individual engines and thedesign of the corresponding propeller may be the same as in theembodiment shown in Fig. 1, the details thereof are not shown in Fig..2. It is preferable to employ, as shown in Fig. 2, a common adjustingdevice 45 for the maintained constant.

adjustment of the regulating values to be maintained constant by thecharging pressure regulator, and a common adjusting device 46 for theadjustment of the regulating values to be maintained by the speedgovernor. Figs. 3 and 4 illustrate a top view of these adjusting devicesand Fig. 5 shows a front elevational view thereof. As will be seen fromthese figures the adjusting device consists of a drum 45a or 46arespectively to which the ends of the control lines are secured andwhich are adjustable by a crank 451) or 45b respectively 7 according toa scale arranged on' the disc 450 or 460 respectively. Theadjustingdevices 45, 45 are arranged at the pilot seat.

, The common adjusting devices for the engines 4| to 44 have theadvantage that all engines are always adjusted to the same speed valueto be This is very important in order to prevent the occurrence ofoscillations caused by variations of the speeds of theengines. Theadjusting device 45 in Figures 2, 3, and 5 consists of or forms part ofthe automatic control device as will be pointed out later.

The automatic controlling device to be used as adjusting device 34 inFigure 1, and 45 in Figure 2, or in connection therewith, is designed toregulate the power of the engines in accordance with the height offlight so as to maintain constant a predetermined height of flight. Thispresupposes that the power of one engine-or if the aeroplane is equippedwith several engines, if

desired, also the power of the several engines-be regulated inaccordance with a device responsive to changes in the height or altitudeof the aeroplane, for instance an altimeter. In connection with analtimeter, an adjusting device may be provided to set the regulatingvalue to be automatically maintained. This may be accomplished by theembodiment shown in Fig. 6. The altimeter 50 is designed in the form ofa barometer, i. e., it comprises as the most essential part thereof awholly or partially evacuated chamber 590 which is closed by a diaphragm50b. As is well known variations of the air pressure cause acorresponding variation of the distance of the central portion of thediaphragm from the bottom of the chamber-50a. A contact arm 50d ispivotally mounted as indicatedat 50c and oscillates with one end thereofbetween two counter-contacts 5l' and 52.

These counter-contacts are secured to a worm wheel segment 53 which isactuated by the electric motor 59 through the worm 54, the shaft 55, thebevel gears 56 and 51 and the shaft 58. The motor 59 is, furthermore, inoperative connection with a drum 60 to which are secured the ends offour control lines GI which serve to adjust the regulating value to bemaintained by the charging pressure regulator as disclosed in Figs. 1and 2.

The contact arm 50d extends into the casing of the altimeter 50 and, onthe one hand, cooperates with the diaphragm 501) through an intermediatepiece 62 and, on the other hand, witha spring 53.

. The other end of the spring is secured to a spindle 64 whichcooperates with a nut arranged in the wall of the casing of thealtimeter 50 and may be adjusted on the scale from the pilot seatthrough a flexible shaft 65 by means of the crank handle 66. The scaleI1 is preferably calibrated in heights. The motor 59 is a reversingmotor and is switched in in the one or the other direction dependingupon whether the contact 50d comesinto engagement with thecounter-contact 51 or 52.

The operation is as follows:

At the beginning of -or during the flight the crank'handle 5B is rotateduntil the stationary pointer 11a indicates the desired height of flighton'the scale ll. Such rotation shifts the spindle 64 lengthwise toadjust the tension of the spring 63. If this desired height of flight isgreater than the height of flight actually attained at the moment inquestion the contact arm 50d owing to the actuation of the handle 66comes into engagement with one of the counter-contacts 5| and 52. Themotor 59 is switched in in one direction-of rotation and the regulatingvalue to be maintained by the charging pressure regulator is increasedto the required extent. The parts 5| to 53 form in this case thewell-known transmission arrangement employed in regulating devices.

Thesame operation will take place if the actual height of flight differsfrom the desired height of flight, for instance, as the result of agust. In this case also, the contact arm 50d comes into engagement withone of the counter-contacts 5|,

. 52 depending upon the departureirom the desired whole device of Fig. 6takes the place of device 45 in Fig. 2 so that drum lili replaces thedrum 45a, and handle 66 and scale 11 replace parts 456 and 450 (Figs. 3and 5) of device 45.

The adjusting device 84 in conjunction with the rack Ild and the partsconnecting them constitute a device for changing the setting of thegovernor Ii. Similarly, the adjusting device 84 in conjunction with therod 21 and the parts connecting them constitute a device for changingthe setting of the pressure-responsive means It. Again, in Fig. 6 thealtimeter constitutes means responsive to pressure, such means being setaccording to the tension of the spring 63, and the parts 54, 66,-", 110.constitute a device for changing the setting of said pressure-.

responsive means.

I claim as my invention:

1. In an aircraft having a driving propeller of variable pitch, thecombination of an internal combustion engine for driving said propeller,said engine having a connection for supplying a gaseous driving mediumthereto at a variable charging pressure and controlling means forvarying said charging pressure, means for governing the pitch of saidpropeller for maintaining said engine at a constant speed, a devicerespon-.

sive to changes in the altitude of said aircraft, said device beingoperatively connected with said controlling means so as to adjust saidcharging pressurein response to changes in altitude in order to maintaina' predetermined altitude of said craft by said adjustment of thecharging pressure.

2. In an aircraft having a driving propeller designed to be operatedwith variable pitch, the combination of an internal combustion enginedisposed to drive said propeller and designed to be supplied with agaseous fuel of variable charging pressure, a device for governing thepitch of said propeller so as to maintain said engine at a constantspeed, means for controlling said charging pressure, an altimeteroperatively connected with said controlling means so as to adjust saidcharging pressure in response to changes in altitude in orderto-maintain a predetermined altitude by said adjustment.

3. In an aircraft having a driving propeller designed to be operatedwith variable pitch, the combination of aninternal combustion engine.disposed to drive said propeller and designed to be supplied with agaseous fuel of variable charging pressure, means for governing thepitch of said propeller so as to maintain said'engine drlvingmedium at avariable charging pressure, a

governor for automatically maintaining said engine at a constant speed,means for controlling ,said charging premure, an altimeter operativelyconnected with said controlling means in order to change said chargingpressure according to .changes in the altitude of said aircraft so as tomaintain a predetermined altitude, and a device for altering the settingof said altimeter.

dependent of changes in said condition 5. In an aircraft, thecombination of a plurality of variable pitch propellers for driving saidcraft, a plurality of internal combustion engines each being connectedto one of said propellers and designed to be supplied with a gaseousdriving medium of variable charging pressure, means for governing thepitch of said propellers for maintaining said engines at a constantspeed, a device responsive to changes in the altitude of said aircraft,and a plurality of individual means for controlling the chargingpressure at said engines, each of said means being allotted to one ofsaid engines and operatively connected with said device so as to adjustsaid charging pressure in response to changes in altitude in order tomaintain said craft at a predetermined altitude.

6. In a propeller-driven aircraft, the combina tion of a plurality ofinternal combustion engines for driving the propellers of said craft,each engine having a connection for supplying a gaseous driving mediumthereto at a variable char ing pressure and means for controlling sawcharging pressure, governor operated means fw maintaining said enginesat a constant specs an altimeter operatively connected with said controlling means for adjustin gthe charging pressure at the respectiveengines in response t changes in the altitude of said aircraft so as inmaintain a predetermined altitude.

"I. In an aircraft having, a variable pitch pro peller and an internalcombustion engine for driving said propeller, incombination, means forsupplying said engine with a gaseous driving me dium of variablecharging pressure, pressureregulating means for maintaining saidcharging pressure at a constant value, mechanism" for governing thepitch of said propeller so as to maintain said propeller at a constantspeed, a device for adjusting said governing mechanism as to the speedto be kept constant, a device for ad-- justing said pressure-regulatingmeans, and control means responsive to a condition of fligili, saidcontrol means being operatively connected with one of said adjustingdevices for setting said latter adjusting device so as to maintain saidengine at a constant power independent of changes in said condition offlight.

8. In an aircraft having a variable pitch propeller and an internalcombustion engine for driving said propeller, in combination, means forsupplying said engine with agaseous Jiriving medium of variable chargingpressure, pressure-regulating means for maintaining sai chargingpressure at a constant value, mechanism for governing the pitch of saidpropeller so as to maintain said propeller at a constant speed, a devicefor adjusting said governing mechanism as to the speed to be keptconstant, anda control device responsive to a condition of flight, saidcontrol device being operatively connected with said pressure-regulatingmeans for adjusting said latter means so as to maintain the power ofsaid engine at a constant value inof flight.

9. In an aircraft having a variable pitch propeller and an internalcombustion engine for driving said propeller, in combination, means forsupplying said engine with a gaseous driving medium of variable chargingpressure,'pressureregulating means for maintaining said charge ingpressure constant at an adjusted value, and governing means forcontrolling the pitch of said propeller so as to maintain the speed ofsaid propeller at an adjusted value, said presbeing adjusted to maintainthe power of said engine constant at a maximum value.

10. In an aircraft having a variable pitch propeller and an internalcombustion engine fordriving said propeller, the combination of meansfor supplying said engine with gaseous fuel of variable chargingpressure, pressure-regulating device for maintaining said chargingpressure at a constant value, a setting device for adjusting saidpressure-regulating device, hydraulic drive, a valve for controllingsaid drive, a connection between said valve and said setting device, andanother connection between said drive and said pressure regulatingdevice, in combination with a speed-responsive governor connected withsaid engine, means for varying the pitch of said propeller, an hydraulicdrive interposed between said governor and said pitch-varying means,said latter drive also having a control valve, another setting deviceconnected with said latter valve for setting a speed value to be keptconstant by said governor and said pitch-varying means, and a controldevice responsive to a condition of flight forming part of one of saidconnections so as to superpose on the appertaining valve an additionalcontrol adjustment independent of said setting means, said two settingmeans being manually adjustable and located at the pilots seat, wherebythe power output is automatically kept constant at a selectable value tobe set by the pilot.

11. In anaircraft having a variable pitch propeller with means foradjusting the propeller blades and an internal combustion engine fordriving said propeller, in combination, means for supplying said enginewith a gaseous medium of a predetermined charging pressure,pressureregulating means for maintaining said pressure constant at saidpredetermined value, said regulating means being responsive to thevariations of said charging pressure, controlling means for adjustingthe base value of said charging pressure, means for maintaining thespeed of the propeller constant including a speed governor controllingthe speed of the propeller, said governor cooperating with saidadjusting means of the propeller blades, and means for varying the basevalue of said speed governor.

12. In an aircraft having a variable pitch propeller and an internalcombustion engine for driving said propeller, in combination, means forsupplying said engine with gaseous fuel of variable charging pressure,pressure-regulating means for maintaining said charging pressureconstant at an adjusted value, and governing means for controlling thepitch of said propeller so as to maintain the speed of said propeller atan adjusted value, said pressure-regulating means and said governingmeans being adjusted to maintain the power of said engine constant at apredetermined value.

PAUL EDUARD KCSSTER.

